<style>
    ul {
        margin: 0;
        padding: 0;
        text-align: center;
        list-style-type: none;
    }
    a {
        color: black;
        text-decoration: none;
    }
    a:hover {
        text-decoration: underline;
    }
    #contents {
        position: relative;
        overflow: hidden;
    }
    #links {
        width: 110px;
        float: left;
        padding: 5px;
    }
    #background {
        width: 120px;
        position: absolute;
        float: left;
        left: 0;
        bottom: 0;
        top: 0;
        background: cyan;
        border: 1px solid black;
        z-index: -10000;
    }
</style>
<body>
    <div id=contents>
        <div id=links>
            <ul>
                <li><a href="welcome.html">Home 1</a></li>
                <li><a href="welcome.html">Home 2</a></li>
                <li><a href="welcome.html">Home 3</a></li>
            </ul>
        </div>
        <div id=background></div>
    </div>
</body>
